1. Field of the Invention
This invention relates generally to pressurized fluid devices and, more particularly, to improved structure for introducing pressurized fluid into such devices in a simplified, rapid and reliable manner.
2. The Prior Art
In a device known from German Offenlegungsschrift No. 19 25 963 (see U.S. Pat. No. Re. 28,329), the piston rod is provided with a section of reduced diameter, which section is adapted to be brought into radial alignment with a sealing member fixedly mounted to the container, or cylinder, at the point where the piston rod enters the container, so that the pressurized fluid can pass through a gap between the piston rod and the piston rod passage and across the sealing member. After filling, however, care must be taken that the reduced diameter section of the piston rod does not again come into radial alignment with the sealing member, because in such case the pressurized fluid could escape. Further, the section of reduced diameter must be very carefully machined in order to prevent damage to the sealing member, since the sealing member must prevent leakage of the pressurized fluid during normal operation of the device.
It is further known from German Gebrauchsmuster No. 74 22 901 to fill the container cavity through a gap between the piston rod passage and the piston rod across a lip-shaped sealing member fixed at the piston rod passage, the lip-shaped sealing member acting as a check valve, which opens under the action of an outer filling pressure and sealingly engages the piston rod under the action of the pressure of the fluid within the cavity. Such lip-shaped sealing members must be manufactured very precisely and have a complicated shape, so that their manufacture is expensive. Such lip-shaped sealing members, moreover, must be supported by a supporting member, which must also be shaped very precisely.